jet ventilation (HFJV) is provided by the Bunnell Life Pulse High-Frequency Ventilator. HFJV employs an endotracheal tube adaptor in place for the normal 15 mm ET tube adaptor. A high pressure "jet" of gas flows out of the adaptor and into the airway. This jet of gas occurs for a very brief duration, about 0.02 seconds, and at high-frequency: 4-11 hertz. Tidal volumes ≤ 1 ml/Kg are used during HFJV. This combination of small tidal volumes delivered for very short periods of time creates the lowest possible distal airway and alveolar pressures produced by a mechanical ventilator. Exhalation is passive. Jet ventilators utilize various I:E ratios—between 1:1.1 and 1:12—to help achieve optimal exhalation. Conventional mechanical breaths are sometimes used to aid in reinflating the lung. Optimal PEEP is used to maintain alveolar inflation and promote ventilation-to-perfusion matching. Jet ventilation has been shown to reduce ventilator induced lung injury by as much as 20%. Usage of high-frequency jet ventilation is recommended in neonates and adults with severe lung injury. Indications for use The Bunnell Life Pulse High-Frequency Ventilator is indicated for use in ventilating critically ill infants with pulmonary interstitial emphysema (PIE). Infants studied ranged in birth weight from 750 to 3529 grams and in gestation age from 24 to 41 weeks. The Bunnell Life Pulse High-Frequency Ventilator is also indicated for use in ventilating critically ill infants with respiratory distress syndrome (RDS) complicated by pulmonary air leaks who are, in the opinion of their physicians, failing on conventional ventilation. Infants of this description studied ranged in birth weight from 600 to 3660 grams and in gestational age from 24 to 38 weeks. Adverse effects The adverse side effects noted during the use of high-frequency ventilation include those commonly found during the use of conventional positive pressure ventilators. These adverse effects include: Pneumothorax Pneumopericardium Pneumoperitoneum Pneumomediastinum Pulmonary interstitial emphysema Intraventricular hemorrhage Necrotizing tracheobronchitis Bronchopulmonary dysplasia Contraindications High-frequency jet ventilation is contraindicated in patients requiring tracheal tubes smaller than 2.5 mm ID. Settings and parameters Settings that can be adjusted in HFJV include 1) inspiratory time, 2) driving pressure, 3) frequency, 4) FiO2, and 5) humidity. Increases in FiO2, inspiratory time, and frequency improve oxygenation (by increasing "auto-PEEP" or pause pressure), while an increase in driving pressure and a decrease in frequency improve ventilation. Peak inspiratory pressure (PIP) The peak inspiratory pressure (PIP) window displays the average PIP. During startup a PIP